1. Field of the Invention
This invention relates generally to assistive mobility devices and more particularly to a collapsible upright wheeled weight-bearing walker.
2. Description of the Related Art
Assistive mobility devices, including walkers, are well-known in the art as useful means for reducing the disadvantages of mobility impairment suffered for many different reasons by many people, permitting more efficient ambulation over distance and thereby increased independence. Data from the National Long Term Care Survey suggests that increased use of assistive technology may have helped reduce disability at older ages [Manton, et al., “Changes in the Use of Personal Assistance and Special Equipment from 1982 to 1989: Results from the 1982 and 1989 NLTCS,” Gerontologist 33(2):168-76 (April 1993)]. Although mobility device users represent a relatively small minority of the population with disabilities, their importance transcends their numbers because mobility devices are visible signs of disability and have become symbols of the very idea of disability. And the mobility-impaired population is increasing much faster than the general population [LaPlante et al., “Demographics and Trends in Wheeled Mobility Equipment Use and Accessibility in the Community,” Assistive Technology, 22, 3-17, (2010)]. Accordingly, there has long been a growing demand for improved mobility assistance devices adaptable for improving ambulation for mobility-limited persons.
Martins et al. [Martins et al., Assistive Mobility Devices focusing on Smart Walkers: Classification and Review, Robotics and Autonomous Systems 60 (4), April 2012, pp. 548-562] classifies mobility assistance devices into the alternative devices intended for those with total loss of independent mobility (wheelchairs or autonomous powered vehicles) and assistive or augmentative devices for those with residual mobility capacity (prostheses, crutches, canes and walkers). For several reasons, most impaired individuals prefer to avoid association with the alternative devices associated with total incapacity. Similarly, the rehabilitation profession strongly prefers the assistive devices, which can be used for physical therapy and as mobility-training devices. Accordingly, there has long been a growing demand for improved assistive devices adapted for use by the less disabled among those who otherwise cannot move independently with existing assistive devices and rely on alternative devices such as wheelchairs and powered scooters.
Mobility and manipulation are critical to living independently and are often strongly associated with the ability to continue to live safely in one's home. Simple assistive devices such as crutches, canes, walkers, and rollators (rolling walkers) can assist a person who has the endurance and strength to walk distances, but these devices must also provide some support or feedback to keep the person from losing their balance or enable the person to rest, when necessary. Although an impaired individual may eventually need an alternative device like a wheelchair or powered scooter, most strongly desire to retain the independence of the simpler assistive device for as long as possible. For this reason, there is a well-known and long-felt need for assistive device improvements that facilitate independent ambulation for the progressively more impaired individuals.
Although popular, the most common assistive devices known in the art (canes, walkers and rollators) have many well-known disadvantages; even for the relatively mobile individual.
The typical wheeled walker known in the art has many well-known disadvantages; such as requiring a stooping or a forward leaning posture to avoid a hobbled gait, difficulty in smooth transition over irregular terrain, little or no upper body and arm support, and requiring significant hand and arm strength to maneuver and to operate any available hand brake, for example. A stooping posture stresses the user's back and arms and risks tipping forward when encountering terrain obstacles. And most devices known in the art have no wheels or wheels too small to negotiate even small surface irregularities safely. Some devices are too heavy and awkward for an unassisted user to lift into a car trunk or van, which limits independent unassisted use. Walker brakes are often either nonexistent or ineffective for the unassisted impaired user, which adds risk of falls and injury and limits independence.
The typical wheeled walker known in the art is neither designed nor intended to support significant user weight during use. As with a cane, the accepted purpose of a wheeled walker is simply to provide assistance in balance and gait, like an elaborate cane system. So the user engages the walker with hands and wrists alone, often with a stooping or leaning posture. The impaired user generally lacks the hand and wrist strength needed to continuously support significant upper body weight while walking in a stooped or forward-leaning position. Some wheeled walkers eliminate the seat to afford a more open walking footprint for the user. While this permits an improved and more natural walking position but offers no improved weight bearing capability and many users need an included seat to facilitate independent use over longer distances.
The mobility assistance art is replete with suggestions for improving wheeled walkers.
For example, in U.S. Pat. No. 8,100,415, Kindberg et al. disclose a wheel suspension that facilitates curb climbing when used with large wheels in, for example, a rollator. But Kindberg et al. limit their teachings to negotiating uneven terrain such as curbs. In U.S. Pat. No. D561,065, Kindberg et al. also disclose a walker frame design.
And, for example, in U.S. Pat. No. 8,840,124, Serhan et al. disclose a safety brake in a rollator that improves the safety of seated users by using a braking system that locks the rollator wheels when the user sits down on the rollator seat, and releases the wheels when the user stands up. As another example, in U.S. Pat. No. 7,052,030, Serhan discloses a wheeled walker with cross-member supports adapted to permit both seat and basket with wheel sizes greater than seven to eight inches. In U.S. Pat. No. 6,886,575, Diamond discloses a locking assembly for use with a walker having foldable side members. And, for example, in U.S. Pat. No. 8,678,425, Schaaper et al. disclose a wheelchair having a moveable seat element facilitating use as a rollator.
In U.S. Pat. No. 8,740,242, Slomp discloses a posterior walker configured to encourage a neutral spine during use. And, for example, in U.S. Pat. No. 7,559,560, Li et al. discloses a rollator having a foldable seat element.
Some practitioners propose improving the walker mobility aid by adding upper support means for supporting the user's forearms, hands or shoulders to improve user comfort and posture. For example, in U.S. Pat. No. 5,657,783, Sisko et al. disclose accessory forearm rests that may be mounted to any conventional invalid walker, preferably disposed above the normal hand-grips to provide support for the user's arms.
Such an upright wheeled walker may permit the user to walk upright but the wheeled walker known in the art is not adapted to support any user body weight beyond the relatively small portion in the forearms and hands. For example, in U.S. Pat. No. 8,540,256, Simpson discloses a walker with a forearm support frame to permit an upright user to step forward with the walker footprint but little weight bearing capacity. Similarly, in U.S. Pat. No. 8,740,242, Slomp discloses a foldable posterior walker with an anteriorly open frame that permits an upright user to step forward within the walker footprint but having little or no weight bearing capability.
Improving a the wheeled walker by adding an upper-body support is advantageous because it facilitates an upright walking and standing posture, improved gait and comfort. But adding significant user body weight to the wheeled walker is also disadvantageous for stability. The increased weight borne on each wheel affects walker stability, braking, and terrain handling. For example, adding significant upright weight support to the wheeled walker introduces new disadvantages of increased lateral and longitudinal instability, risking falls and affecting user safety. Adding more weight support at a higher point on the walker increases the tipping torque at the wheels because of the increased force and distance. Any wheeled walker has longitudinal stability problems when rolling on slopes and over irregular terrain, which may imperil user safety by causing falls during use. This longitudinal instability problem is exacerbated by the fluctuating wheel loads imposed by the applied user weight during stepping, introducing a new lateral instability.
Several practitioners suggest improvements to mitigate the wheeled walker longitudinal stability problem with braking system improvements. For example, in U.S. Pat. No. 8,998,223. Chang discloses a wheel braking system for a rollator with a “dead-man brake” whereby the wheels are halted upon the release of the user's hands from the handles, improving user safety on slopes. Similarly, in U.S. Pat. No. 9,221,433, Dunlap discloses a safety braking system for a rollator that includes a park mode, a walk mode and a brake mode with a handlebar control mechanism.
Recognizing these new instability problems, practitioners have suggested turning to a powered vehicle to permit some user weight support in assistive devices. For example, in U.S. Pat. No. 8,794,252, Alghazi discloses a mobility apparatus with an integrated power source and four wheels so a user can stand on it and drive it as an electric mobility device, or disable it and use it as a passive walker. His device is collapsible and includes a pair of supporting beams disposed to support the user under the armpits, but such support does little to improve user posture or stability while walking with the passive device. And, in U.S. Pat. No. 8,234,009, Kitahama discloses an autonomous mobile apparatus that moves autonomously along near a specified person (user) while detecting and evaluating the surroundings to assess the danger level to the user, moving as necessary to avoid danger to the user based on the danger level detected.
Others have proposed elaborate powered control systems to address these stability and other user safety problems. For example, in U.S. Pat. No. 7,708,120, Einbinder discloses an improvement to user safety consisting of a walker braking system using a controller and electrically actuated wheel brakes to provide push-button user control over braking and processor-controlled braking responsive to, for example, user hand position and the terrain slope.
But such devices may be generally perceived by users as alternative devices (such as powered wheel chairs, stair climbers and vehicles) and do not represent the improved assistive device sought by most users.
These and other examples of the mobility assistance art demonstrate that there is a continuing long-felt need for improved solutions to the walking posture, seating, weight support and portability problems discussed above.
These unresolved problems and deficiencies are clearly felt in the art and are solved by this invention in the manner described below.